Shadows cast below the ground

[djh]

How may one fix a model so that the shadows don't cast below the ground? The model/object is exactly at the point where the red/blue/green axes meet, yet the shadow is cast below the ground.

Solved my own problem.
Somehow, the axes moved above their original position. Right clicked one axis/reset.

[Dave R]

It's worth noting that the ground plane is fixed. The red and green model axes are, by default, on the ground plane. The axes can be moved and reorient ed but the ground plane cannot be moved.